Question about Dometic Rooftop RV Air Conditioner

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Recharge My AC Unit

I have a coleman mach series  roof top ac unit that does not blow cold air but everything works on it. I found where the freon leaked out and can solder it but do not know how to refill the freon. Any advise?

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The system needs to be accessed through what is call a tap valve. After a tap valve is in place a high vacuum should be pulled on the system down to 500 microns to remove air and non condensible gases along with any moisture from the system. Then the charge should be weight into the system according to the name plate with the proper type of refrigerant, generally Refrigerant 22. An alternate method is to charge the system by superheat of the gas returning to the compressor. Ambient temperature determines how high or low the superheat should be.

Posted on Jun 20, 2008

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Look on tag to see what refrigerant it uses then go to walmart or other place and pick up a can or two along with a can of A/C oil and a fill hose with gage some come with it on the can, connect it to the low side scharder valve, the connector will only fit the fill valve. Then start the unit and turn on max, and check the gage it should be in the blue when fully charged.Turn the knob to pierce the can of refrigerant and hold can upside down as the A/C fills watch the gage then if you need more add the can of oil and then the second can of refigerant.keep going till you get to the blue full mark about 45, most times a vacuum is not needed as long as there is any refrigerant left at all trapped in system . a vacuum is needed if compressor or dryer ,or reservoir tank is replaced as these store excess air,liquid, and gas.just read directions on filling hose and gage and close tap valve. not much chance of any mistake.

Posted on Jun 05, 2015

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